Individuals who lack a fixed, regular and adequate nighttime residence, including children and youth who lack a fixed, regular and adequate nighttime residence, and children and youth who are sharing the housing of other persons due to loss of housing, economic hardship, or a similar reason; are living in motels, hotels, trailer parks, or camping grounds due to lack of alternative adequate accommodations; are living in emergency or transitional shelters; are abandoned in hospitals; or are awaiting foster care placement.

In 2003, children under the age of 18 accounted for 39 percent of the homeless population; 42 percent of these children were under the age of 5 (National Law Center on Homelessness and Poverty, 2004). This same study found that unaccompanied minors comprised 5 percent of the urban homeless population. However, in other cities and especially in rural areas, the numbers of children experiencing homelessness are much higher.

According to the National Law Center on Homelessness and Poverty, in 2004, 25 percent of homeless were ages 25-34; the same study found percentages of homeless persons aged 55-64 at 6 percent.

Research indicates that 40 percent of homeless men have served in the armed forces, as compared to 34 percent of the general adult population.

Persons with severe mental illness represented about 26 percent of all sheltered homeless persons (Annual Homeless Assessment Report to Congress, 2008). According to the Federal Task Force on Homelessness and Severe Mental Illness, only 5-7 percent of homeless persons with mental illness require institutionalization; most can live in the community with the appropriate supportive housing options.

Many homeless are also victims of domestic violence, and people experiencing recent or chronic unemployment.